A large number of semiconductor devices that are electronic components are built in a wireless communication apparatus represented by a mobile phone. Semiconductor devices are required to suppress an adverse effect of electromagnetic waves to an interior and an exterior like a leakage of electromagnetic waves in order to prevent an adverse effect to communication characteristics. Hence, semiconductor devices which have a shielding function against the electromagnetic waves have been applied.
In general, a semiconductor device is formed by mounting a semiconductor chip on an interposer substrate that is an intermediate substrate to amounting substrate, and by sealing this semiconductor chip by a resin. By providing a conductive electromagnetic wave shielding film on the top face and the side face of this sealing resin, the semiconductor devices achieving the shielding function have been provided (see WO 2013/035819 A).
Such an electromagnetic wave shielding film can be a laminate film of multiple kinds of metals. For example, an electromagnetic wave shielding film is known which employs a laminated structure of forming a Cu film on an SUS film, and further forming an SUS film thereon.
In order to accomplish a sufficient shielding effect for an electromagnetic wave shielding film, it is necessary to decrease the electric resistivity. Hence, the electromagnetic wave shielding film needs to have a thickness to some level.
In semiconductor devices, in general, when a film has a thickness of substantially 1 to 10 μm, an excellent shielding characteristic is expectable. In the case of the above electromagnetic wave shielding film employing the laminated structure of SUS, Cu, and SUS, it is known that, when the thickness is substantially 1 to 5 μm, an excellent shielding effect is expectable.
As a forming method for the electromagnetic wave shielding film, plating method is known. However, since the plating method needs wet processes such as a pre-process step, a plating process step, and a post-process step like wet-cleaning, those result in the increase of the manufacturing cost for a semiconductor device.
Accordingly, sputtering method that is a dry process is getting attention. A plasma processing apparatus that forms a film by plasma has been proposed as a film forming apparatus by sputtering method. The plasma processing apparatus introduces an inactive gas into a vacuum chamber in which a target is placed, and applies a DC voltage. The ions of the plasma inactive gas are caused to be collided with the target of the film formation material, and a film is formed by depositing the material beaten out from the target on a work-piece.
General plasma processing apparatuses are applied for a film formation with a thickness of 10 to several 100 nm that can be formed by a process time of several ten seconds to several minutes. However, as described above, it is necessary to form a film with a thickness in a micron order as the electromagnetic wave shielding film. Since sputtering is a technology of forming a film by depositing particles of the film formation material on an object on which the film is formed, the thicker film thickness lengthens the time required to form a film.
Hence, in order to form the electromagnetic wave shielding film, a processing time of substantially several ten minutes to an hour is necessary which is longer than general sputtering. In the case of, for example, the electromagnetic wave shielding film employing the laminated structure of SUS, Cu, and SUS, a process time of around an hour is necessary in some cases to obtain a thickness of 5 μm.
In this case, according to sputtering method by plasma, a package that is an exterior component of a semiconductor device is continuously exposed to the plasma heat during the process time. Consequently, the package may be heated to a temperature around 200° C. until a film with a thickness of 5 μm is obtained.
In contrast, the heat resistant temperature of the package is substantially 200° C. in the case of a temporal heating of substantially several seconds to several ten seconds, but when the heating time exceeds several minutes, the heat resistant temperature is generally around 150° C. Hence, it is difficult to form the electromagnetic wave shielding film in a micron order by general plasma sputtering method.
In order to address this problem, use of a film material that is magnetic substances, such as Ni and Fe can be considered. Since the magnetic substances have a high shielding effect and can be in a relatively thin film, the heating time by sputtering can be reduced, the temperature rise can be avoided, and the tact time can be reduced. However, when the electromagnetic wave shielding film formed of the magnetic substance is formed on the semiconductor package in practice by sputtering, a desired shielding characteristic to the electromagnetic wave cannot be obtained in some cases.
In addition, the plasma processing apparatus may be provided with cooling means for suppressing the temperature rise of the semiconductor package. In this case, although the apparatus structure becomes complicated and increased, a heating when the electromagnetic wave shielding film including Cu is formed can be reduced. However, for the electromagnetic wave shielding film that is not a magnetic substance, a desired shielding characteristic cannot be obtained in some cases.
An objective of the present disclosure is to provide an electronic component, an electronic component manufacturing apparatus, and an electronic component manufacturing method enabling an electromagnetic wave shielding film formed on a package to achieve an excellent shielding characteristic.